A cellular phone of our country has been put into practical use together with a mobile telephone having a volume of 6800 cm3 and a weight of 7 kg. It can be said that the development of a cellular phone is the history of pursuit of a reduction in size and weight thereof since the commencement of cellular telephony services in 1987. The greatest contribution to the reduction in size and weight of the cellular phone used up to now resides in a size reduction concerning parts. In particular, a great contribution has been made to a size reduction concerning high-frequency parts. Further, an advantageous effect has been brought about in that surface mounting of parts has been put forward and surface-mounting type parts other than the high-frequency parts have been also reduced in size. They have been yielded from the result that an attempt has been made to bring a high-frequency circuit into integration starting with a control-system circuit (baseband signal processing circuit), thereby covering major circuits with less-reduced LSI configurations.
As a package form of the above-described LSI, the adoption of a downsized and multi-pin configured BGA (Ball Grid Array), or CSP (Chip Size Package) has been put forward as an alternative to the conventional QFP (Quad Flat Package). The CSP is called an “ultimate package”. This is because the CSP has both the good point of a bear chip and the good point of a package. Bear-chip mounting is excellent if only the size and weight reduction is taken into consideration. However, the adoption of the CSP has been put forward as a result that the cost, reliability, a framework to supply parts, etc. have been optimized totally.
The CSP varies widely but an external terminal form thereof can be regarded as a small-sized BGA arranged in area array form. It is estimated that minimum terminal pitches of both the BGA and CSP will be further narrowed from now on.
In order to mount multipin-configured/narrow-pitched/small-sized packages such as these BGA and CSP or the like, multilayering of a printed wiring board cannot be avoided either and hence the technology of forming small-diameter vias and fine patterns is essential. A build-up substrate characterized in that the limits of wiring pitches of a conventional substrate have been surmounted to reduce the diameter of each via and enhance the degree of freedom of a via layout, for example, and other high-density printed wiring board have been developed and put into practical use.
In 1996, the model, which has broken the barrier of a volume of 100 cm3 and a weight of 100 g, has debuted as a domestic digital cellular phone but the adoption of the CSP has been started from this year. Thus, the adoption of a newly-developed high-density printed wiring board (a kind of build-up wiring board) becomes a key (NIKKEI ELECTRONICS 1997. 1. 13 (no. 680), PP. 15–16).
A high-frequency composite part (filter chip) obtained by integrally forming various passive parts C, R, L and the like in a ceramic green sheet multilayer structure is used in a portable terminal device. The integration of these passive parts has been effective even in, for example, enhancing reliability, taking measures against EMI, and reducing the cost of assembly of a device even in other than a size reduction (NIKKEI ELECTRONICS 1999. 7. 26 (no. 748), pp140–153).
From exclusive devotion to the size and weight reduction, a tendency to pursue various new functions has been made now while the size, weight, design and the like that many users are easy to accept, which have been achieved up to now, are being maintained. As trends in the building of various functions in a digital cellular phone may be mentioned, for example, the following ones:
(1) A dualband system and a dual mode system for expanding the limit of a call range and enhancing the convenience of a user have been put into practical use. Further, the introduction of a digital communication system which enables roaming (mobile connection) on a world scale, has been put forward.
(2) An Internet connecting function is provided and its expansion has been made.
(3) A device to which a new data communication standard “Bluetooth” has been mounted, has appeared.
(4) Enhancement of the function of reproducing sound and an image. Coping with a multimedia is made.
Owing to developments in high functioning of the cellular phone, as described above, there is a tendency to increase components including a semiconductor and increase current consumption with their increase. Further, a mounting space has been rendered small increasingly. Therefore, a semiconductor to be used has been required to take a further size and thickness reduction and a reduction in power consumption.
The radio transmitting/receiving function of the cellular phone has been applied to respective personal digital assistances using mobile communications. A cellular phone or a PHS is connected to put data communications, wireless internet, etc. into practical use. Further, the radio transmitting/receiving function has been incorporated into the respective personal digital assistances, and its demand has been increased. New-entry makers encounters difficulties in executing unaccustomed design of an RF/IF signal processing circuit of a communication circuit. These makers have a demand for a product obtained by bringing a high-frequency circuit unit into a module, and one obtained by bringing even some of a baseband signal processing circuit into integration and reducing its size.
As shown in FIG. 2, a configuration of a main circuit of a digital cellular phone is largely divided into a radio unit 100 (RF/IF signal processing circuit unit) which handles analog signals of several hundreds of MHz to a few GHz, and a control unit 200 (baseband signal processing circuit unit) which mainly treats with a digital signal.
Since the radio unit 100 (RF/IF signal processing circuit unit) of these handles the analog signals of several hundreds of MHz to a few GHz, parasitic capacitances of patterns and parts influence on circuit characteristics significantly. As a result, the performance of the device, such as an achievable distance of a wave emitted from a terminal, a receivable distance or the like will vary greatly. Therefore, a case-by-case correspondence must be inevitably taken each time a device is designed. Thus, experiences come into play. If the radio unit 100 (RF/IF signal processing circuit) is brought into a module fixed up on one printed wiring board or brought into one chip to enable its introduction, then a device maker unfamiliar with communication apparatuses is easy to design a high-frequency circuit.
Problems developed upon integration of the RF/IF signal processing circuit (radio unit 100) will be mentioned as follows:
(1) Since manufacturing processes increase, cost-down is difficult.
(2) If the cost of an LSI is taken into consideration, it is then desired to perform the integration thereof by a CMOS technology alone. There are known many LSIs using a bipolar technology up to now. In a device unit level using the CMOS technology even in the case of each input signal lying in a GHz band, ones are in the process of being developed in which high frequency characteristics are given as a level equivalent to or greater than a bipolar. Upon integration of these, crosstalk occurs between circuits and hence the performance is degraded.
(3) Passive parts such as a quartz oscillator and a filter are difficult to make integration into an LSI. When these passive parts are externally attached to the LSI, they produce the case that they are affected by noise or give it.
(4) A portion corresponding to an output power amplifier 130 is very high in power as in the case of 3W, 4W or the like, for example, and hence the substrate reaches a very high temperature even in a moment of time. The substrate rises to a temperature of about 130° C., for example. On the other hand, since the high temperature of 130° C. or the like is beyond the limit at a unit where a small signal is handled as in the case of an RF signal processing unit module 160 or the like of FIG. 19, the unit is separated from a functional module.
Next, an attempt to integrate the radio unit 100 (RF/IF signal processing circuit unit) and the control unit 200 (baseband signal processing circuit unit) principally handling the digital signal into the same chip will yield the following problems:
(1) Performance degradation in circuit due to crosstalk developed between a digital signal processing circuit and an analog signal processing circuit is of a large problem. It is necessary to carry out a contrivance of a part layout such as insertion of a ground layer into the corresponding circuit. A more effective measure is to adopt the process of allowing back gates of respective transistors to be completely separated. As a technology effective therefor, a triple wells, an SOI (Silicon On Insulator), etc. may be mentioned. However, the contrivance of the process will lead to a rise in cost.
(2) The control unit 200 (baseband signal processing circuit unit) makes use of a clock which ranges from about 50 MHz to about 200 MHz, for example, and results in a noise source at the side of the radio unit 100 (RF/IF signal processing circuit unit). Such a unit is not set together with the radio unit.
(3) A microcomputer 220, a DSP 211, a channel codec 214, etc. of the control unit 200 (baseband signal processing circuit unit) have a high potential for the occurrence of various specification changes in function. If they are potentially integrated into one chip, it is then not possible to promptly cope with specification changes. The cost rises upon the specification changes.
Although the problems have been presented as described above, it is estimated that the integration of the radio unit 100 (RF/IF signal processing circuit unit) and the control unit 200 (baseband signal processing circuit unit) has been put forward from now.
The LSI for the radio transmitting/receiving device is classified into four of GaAs, bipolar, Bi-CMOS and CMOS from the viewpoint of the manufacturing processes. Since there are upper limits of operating frequencies at their processes, the discrete processes are respectively used according to circuits to thereby design the LSI. However, it is not advisable under the present situation to manufacture a full custom LSI high in integration by the processes for GaAs and Bi-CMOS relatively high in cost from the viewpoint of economical efficiency and the period of development. Mixed-placing the different processes on the same chip is technically difficult except for Bi-CMOS and fails to match economically in most cases. A future trend is estimated to be consolidated into four types of chips using the respective processes.
Next, a method of packaging respective circuits and respective parts onto a printed circuit board (motherboard) involves the following problems:
(1) According to the load map of SIA (Semiconductor Industry Association of USA), which has been published in the end of 1997, the prediction or estimate of minimum terminal pitches of BGA/CSP/flip-chip device has been described in the following manner. In 1997, the IC minimum line width (nm)/BGA pitch (mm)/CSP pitch (mm)/flip-chip device pitch (mm) were respectively of 250 (nm)/1.0 (mm)/0.5 (mm)/0.25 (mm). In 2001, however, they resulted in 150 (nm)/0.8 (mm)/0.4 (mm)/0.15 (mm). Further, they are estimated to reach 100 (nm)/0.65 (mm)/0.3 (mm)/0.1 (mm) respectively in 2006, 70 (nm)/0.65 (mm)/0.25 (mm)/0.07 (mm) respectively in 2009, and 50 (nm)/0.5 (mm)/0.25 (mm)/0.05 (mm) respectively in 2012.
(2) Owing to the adoption of a buildup printed board provided with high-density wirings for enabling the packaging of BGA and CSP whose terminal narrow-pitching has been put forward, for the motherboard, all functions of a cellular phone could be mounted on a single printed wiring board. However, an area in which small-diameter vias, high-density wirings, fine patterns, narrowed land pitches and multilayering are necessary for the motherboard, corresponds to a partial area of the motherboard. A battery, an LCD, a key board, loud speakers, and a microphone or the like, which occupy the most part of an internal volume of the cellular phone, are mounted in other area directly or indirectly via connecting portions. The areas in which these parts are mounted and connected, need little provision of high-density wirings and a multilayer structure. Nevertheless, only a partial area of one printed wiring board cannot be enhanced in wiring density and changed in the number of layers as compared with other areas. Therefore, the whole wiring density and the total number of layers are determined according to a high wiring density and the maximum number of layers required for the partial area. This will incur a needless increase in the cost of the motherboard (printed wiring board).
In view of the above problems, present and future trends toward the integration of the LSI for the radio transmitting/receiving device do not necessarily lead to the integration of a single chip requested by customers. The integration thereof into a plurality of chips is considered. Further, the respective LSIs are expected to result in a CSP which is increasingly multi-functioned, multipin-configured and narrow-pitched, and a packaging form set in a flip-chip format.
The invention of the present application aims to propose the form of supply of components of a radio transmitting/receiving device, wherein a user who introduces components estimated to become increasingly downsized and narrow-pitched, to thereby configure the corresponding radio transmitting/receiving device, is able to configure the corresponding radio transmitting/receiving device even on a motherboard relatively low in cost and held in low-layer/low wiring density, without preparing an expensive motherboard held in multilayer/high wiring density.
Further, the invention of the present application aims to propose the form of supply of components of a radio transmitting/receiving device, wherein even a user having the know how to design a high-frequency circuit is able to easily configure the corresponding radio transmitting/receiving device.